One in 5 persons in poverty is a child <18 years, and this number is growing, especially in the South. Further, 40% of African American and 34% of Hispanic children <18 years live in low-income households, and 55% of poor rural African-American children have less access to health services. Since a majority of public school students are from low-income families in both the South and West, public schools present an opportunity to reach underserved populations on-site with quality healthcare services. For > 2 decades model School-based Health Centers (SBHCs) have been tested to meet health needs of disparity population, but less than 1% of public elementary schools house SBHCs. Four issues must be addressed in taking SBHCs to scale: sustainability, evidence of community need and support, evidence of health and health cost impact, and fidelity to exemplar models. The ongoing Georgia SBHC Project provides operational solutions to the first two issues. The goal of the proposed study, EPOCH (Evaluating Processes and Outcomes for Children), will take advantage of an opportunity to conduct a natural experiment that will assess the ability of this approach to solve the other two issues. We will examine the effects of expanding SBHCs across three public elementary school sites in Georgia that differ by environment (rural, small city, and suburban) and race / ethnicity (one each being predominantly African American, Hispanic, and non-Hispanic white children). A specific focus will be the effects of SBHCs on improved access to primary care and, in turn, on the level of health outcomes including obesity, uncontrolled asthma, and Emergency Department and hospital utilization and costs to the Medicaid program. We will conduct a year-by-year comparison of health indicators and health care costs for children with and without access to SBHCs. In a novel approach to evaluating SBHCs, we will conduct a full-scale process and outcome evaluation, following the Implementation Fidelity model proposed by Carroll, et al., and modified by Hasson. This will include active monitoring to measure program adaptations, secondary analysis of SBHCs' benchmarking, schools' routine FitnessGrams and absenteeism statistics, and by linking children enrolled in an SBHC to their Medicaid claims records. This quasi-experimental, longitudinal study will include 7 years' data (3 pre-, 1 during, and 3 post-SBHC implementation) for the 3 SBHC schools and 3 similar, non-SBHC schools. Additionally, Medicaid data will be extracted for children living in the 6 schools' zip codes to conduct utilization and cost analyses on improving specific health outcomes (e.g., asthma and obesity) and reducing health disparities in rural and minority populations. The EPOCH study offers an opportunity to create a new evidence base for the role of SBHCs in states without the Medicaid expansion. Comprehensive SBHCs may have greater importance there because of the lack of alternatives for children to access free or subsidized health care. These findings will also inform the nation as it considers reauthorization of the Children's Health Insurance Program (CHIP) in 2015.